WordPress/wp-includes/ms-files.php

<?php
/**
 * Multisite upload handler.
 *
 * @since 3.0.0
 *
 * @package WordPress
 * @subpackage Multisite
 */

if ( ! defined( 'SHORTINIT' ) ) {
	define( 'SHORTINIT', true );
	require_once( dirname( dirname( __FILE__ ) ) . '/wp-load.php' );
}

ms_default_constants( 'ms-files' );

error_reporting(0);

if ( $current_blog->archived == '1' || $current_blog->spam == '1' || $current_blog->deleted == '1' ) {
	status_header( 404 );
	die( '404 &#8212; File not found.' );
}

if ( !function_exists('wp_check_filetype') ) :
function wp_check_filetype($filename, $mimes = null) {
	// Accepted MIME types are set here as PCRE unless provided.
	$mimes = is_array($mimes) ? $mimes : array (
		'jpg|jpeg|jpe' => 'image/jpeg',
		'gif' => 'image/gif',
		'png' => 'image/png',
		'bmp' => 'image/bmp',
		'tif|tiff' => 'image/tiff',
		'ico' => 'image/x-icon',
		'asf|asx|wax|wmv|wmx' => 'video/asf',
		'avi' => 'video/avi',
		'mov|qt' => 'video/quicktime',
		'mpeg|mpg|mpe' => 'video/mpeg',
		'txt|c|cc|h' => 'text/plain',
		'rtx' => 'text/richtext',
		'css' => 'text/css',
		'htm|html' => 'text/html',
		'mp3|mp4' => 'audio/mpeg',
		'ra|ram' => 'audio/x-realaudio',
		'wav' => 'audio/wav',
		'ogg' => 'audio/ogg',
		'mid|midi' => 'audio/midi',
		'wma' => 'audio/wma',
		'rtf' => 'application/rtf',
		'js' => 'application/javascript',
		'pdf' => 'application/pdf',
		'doc' => 'application/msword',
		'pot|pps|ppt' => 'application/vnd.ms-powerpoint',
		'wri' => 'application/vnd.ms-write',
		'xla|xls|xlt|xlw' => 'application/vnd.ms-excel',
		'mdb' => 'application/vnd.ms-access',
		'mpp' => 'application/vnd.ms-project',
		'swf' => 'application/x-shockwave-flash',
		'class' => 'application/java',
		'tar' => 'application/x-tar',
		'zip' => 'application/zip',
		'gz|gzip' => 'application/x-gzip',
		'exe' => 'application/x-msdownload'
	);

	$type = false;
	$ext = false;

	foreach ( (array) $mimes as $ext_preg => $mime_match ) {
		$ext_preg = '!\.(' . $ext_preg . ')$!i';
		if ( preg_match($ext_preg, $filename, $ext_matches) ) {
			$type = $mime_match;
			$ext = $ext_matches[1];
			break;
		}
	}

	return compact('ext', 'type');
}
endif;

$file = BLOGUPLOADDIR . str_replace( '..', '', $_GET[ 'file' ] );
if ( !is_file( $file ) ) {
	status_header( 404 );
	die( '404 &#8212; File not found.' );
}

$mime = wp_check_filetype( $_SERVER[ 'REQUEST_URI' ] );
if( false === $mime[ 'type' ] && function_exists( 'mime_content_type' ) )
	$mime[ 'type' ] = mime_content_type( $file );

if( $mime[ 'type' ] )
	$mimetype = $mime[ 'type' ];
else
	$mimetype = 'image/' . substr( $_SERVER[ 'REQUEST_URI' ], strrpos( $_SERVER[ 'REQUEST_URI' ], '.' ) + 1 );

header( 'Content-type: ' . $mimetype ); // always send this
if ( false === strpos( $_SERVER['SERVER_SOFTWARE'], 'Microsoft-IIS' ) )
	header( 'Content-Length: ' . filesize( $file ) );

// Optional support for X-Sendfile and X-Accel-Redirect
if ( WPMU_ACCEL_REDIRECT ) {
	header( 'X-Accel-Redirect: ' . str_replace( WP_CONTENT_DIR, '', $file ) );
	exit;
} elseif ( WPMU_SENDFILE ) {
	header( 'X-Sendfile: ' . $file );
	exit;
}

$last_modified = gmdate( 'D, d M Y H:i:s', filemtime( $file ) );
$etag = '"' . md5( $last_modified ) . '"';
header( "Last-Modified: $last_modified GMT" );
header( 'ETag: ' . $etag );
header( 'Expires: ' . gmdate( 'D, d M Y H:i:s', time() + 100000000 ) . ' GMT' );

// Support for Conditional GET
$client_etag = isset( $_SERVER['HTTP_IF_NONE_MATCH'] ) ? stripslashes( $_SERVER['HTTP_IF_NONE_MATCH'] ) : false;

if( ! isset( $_SERVER['HTTP_IF_MODIFIED_SINCE'] ) )
	$_SERVER['HTTP_IF_MODIFIED_SINCE'] = false;

$client_last_modified = trim( $_SERVER['HTTP_IF_MODIFIED_SINCE'] );
// If string is empty, return 0. If not, attempt to parse into a timestamp
$client_modified_timestamp = $client_last_modified ? strtotime( $client_last_modified ) : 0;

// Make a timestamp for our most recent modification...
$modified_timestamp = strtotime($last_modified);

if ( ( $client_last_modified && $client_etag )
	? ( ( $client_modified_timestamp >= $modified_timestamp) && ( $client_etag == $etag ) )
	: ( ( $client_modified_timestamp >= $modified_timestamp) || ( $client_etag == $etag ) )
	) {
	status_header( 304 );
	exit;
}

// If we made it this far, just serve the file
readfile( $file );

?>